Talks

Spectral analysis serves as a fundamental diagnostic tool for understanding emission mechanisms, propagation effects, and interactions between pulsar radiation and surrounding material—particularly in binary systems. Fast Radio Bursts (FRBs) often exhibit complex spectral features such as band-limited emission and temporal variability, the origins of which remain poorly understood. Binary millisecond pulsars (MSPs), particularly those showing gigahertz-peaked spectra (GPS) and variable turnover frequencies, offer valuable analogs for probing these effects in a controlled Galactic setting.  Temporal variations in pulsar spectra can provide insights into propagation through the interstellar medium (ISM), and help disentangle intrinsic effects such as GPS, occasionally observed in binary millisecond pulsars. Given the proposed link between compact binaries and fast radio burst (FRB) progenitors, studying spectral evolution in Galactic binary pulsars becomes essential for interpreting FRB phenomenology, including band-limited structures and variability. In this work, we present a case study of PSR J2144–5237, a binary MSP with a 10-day orbital period, and demonstrate a methodology for tracking temporal spectral changes. Our results highlight how binary interactions and variable plasma environments can imprint time-dependent spectral signatures, offering key parallels to FRB behavior. Developing such tools and applying them to Galactic binaries may provide critical insights into the physical conditions driving FRB emission and its variability. The tools developed in our research offer a pathway toward bridging pulsar and FRB studies by applying insights from well-characterized Galactic systems to their extragalactic analogues.

With increasingly precise measurements of the small-scale cosmic microwave background (CMB), the kinetic Sunyaev–Zel’dovich (kSZ) effect has emerged as a powerful probe of cosmology and astrophysics through cross-correlations with galaxy surveys. In this talk, I will review established applications, focusing on large-scale velocity reconstruction and its ability to test signatures of the early universe, such as primordial non-Gaussianity and compensated isocurvature perturbations. I will then introduce a new way to combine these data sets, which provides unique constraints on the distribution of ‘missing baryons’ at low redshifts, thereby opening a new window on baryonic feedback and cosmological inferences from the small-scale distribution of matter. Finally, I will explore the sensitivity of this statistic to the epoch of helium reionization, and compare its prospects to other proposed probes such as optical-depth fluctuations in the observed CMB.